Aldis Signal/Spot Light Kit and Lenses Ref No 5A/823 RCAF 1940-43 KC-97 The Master Indicator was part

The Master Indicator was part of a 5 module system combining the functions of a directional indicator and a magnetic compass

perhaps evidence of its use in the US Navy's version of the B-17

Here is an early WWII-era US Navy aircraft Pelorus Drift Sight

all in good condition

It appears that they also published technical references and catalogs such as this in an effort to expand their service offerings to their customers

Aldis Signal/Spot Light Kit and Lenses Ref No 5A/823 RCAF 1940-43 KC-97 The Master Indicator was partHere is an original WWII era Aldis Signal Light Kit as used by the Royal Canadian Air Force. The light was used either as a spotlight (by squeezing and holding the large trigger) or as a signal light (by squeezing the small trigger, which altered the angle of the projected light) to transmit Morse code. Atop the light housing is a tubular sight to ensure that the light is aimed at the intended recipient to ensure accurate interpretation of any Morse